Abstract: A cognitive radio is a smart radio that can identify the idle frequencies (also termed as spectral holes or white spaces) and allot them for the use of unlicensed secondary users. The basic functionality of a cognitive radio is to sense the spectrum accurately by avoiding any chances for interfering with primary or licensed users. Spectrum sensing can be performed either by cooperative or non-cooperative method. This paper includes co-opertive as well as non-cooperative spectrum sensing techniques. In this paper three techniques of spectrum sensing has been considered that are Energy detection technique, cyclostationary techniques and Eigen value technique. The comparison of these techniques is done on AWGN channel. Performance matrix like probability of miss, probability of detection and signal to noise ratio (SNR) are computed to measure the performance.

Keywords: Cognitive Radio, spectrum Sensing, Dynamic spectrum, Probility of Detection, SNR.